DIGESTION AND WINTER FEEDING. 31 



among scientists, that each part can be strengthened by 

 appropriate feeding ; thus, blood-corpuscles are promoted by 

 the feeding of iron. Non-azotized or farinaceous food favors 

 the formation of fats ; and those rich in albuminoids or 

 nitrogenous matters develop the bones, and give tone and 

 quality to the muscles. 



This development by special feeding is quite often in- 

 stanced in the case of the honey-bee {Apis mellifera). If by 

 any chance the hive is deprived of its queen, the bees choose 

 a cell intended for a neuter, enlarge it somewhat by destroy- 

 ing those around it ; and when the larvae emerges, it is fed 

 with what apiarists term royal jelly, — an aliment of a very 

 stimulating nature, and quite different from the bee-bread 

 intended for the workers. The neuter thus treated comes 

 out a different creature from what was the original intention, 

 for it becomes a true queen. The sexual organs are per- 

 fected, the proportionate length of the body and wings are 

 changed, and also the shape of the sting, tongue, and jaws. 

 The hollow in the thighs, in which the pollen is carried, has 

 wholly disappeared ; and the power to secrete wax has been 

 lost. It is supposed that the greater part of this change has 

 been brought about by feeding. 



There are two prominent sources of demand for food, — 

 the waste of the body, of which we have just spoken, and 

 the maintenance of animal heat ; for in all the higher ani- 

 mals and birds, and to a limited extent in insects, there is 

 a process going on analogous to ordinary combustion. The 

 carbon and hydrogen which are directly supplied by the food, 

 or which have for the time been employed in the composition 

 of the body, are set free by the union of ox3'gen obtained by 

 respiration, and give off as much heat as though the same 

 materials had been consumed by fire in a furnace. 



It is perhaps proper to remark, that the evolution of heat 

 is not confined to the animal kingdom alone : the higher 

 orders of plant-life show by many curious experiments that 

 they possess it to an eminent degree. 



The temperatures of mammalia ranges from 90° to 104°, 

 although higher temperatures are sometimes found ; and, 

 singularly enough, those animals inhabiting the coldest 

 regions have shown it to the greatest degree, the arctic 

 fox having been found to give a temperature of 107° when 



